For Strikeforce welterweight champion Nick Diaz, it was business as usual.

Well, UFC co-owners Dana White and Lorenzo Fertitta were on hand for his defense of the Strikeforce welterweight title, and he proved victorious in one of the most entertaining one-round fights in the promotion’s history, but other than that, you know, just business as usual.

In typical Diaz fashion, the Californian taunted, talked and slugged his way to victory over a game Paul Daley in an instant-classic main event at Saturday’s Showtime-broadcast “Strikeforce: Diaz vs. Daley” event, which took place at Valley View Casino Center in San Diego, Calif.

Diaz started in typical fashion, with his hands low and wide, his chin forward and his mouth running. While the champ professed his respect pre-fight for Daley’s knockout power, he showed little of that at the opening bell. He’d soon learn a bit more appreciation.

After a little back-and-forth action to open, Diaz was caught flush by Daley’s trademark left hook, and the 209 gasped as he hit the canvas. Bobbing and weaving on the floor like a snakewrangler looking to avoid a cobra strike, Diaz avoided a finishing blast from “Semtex” The Brit did score with a shocking soccer kick that just missed the head, but referee “Big” John McCarthy recognized the blow has not crossed any lines.

Back on the feet, Diaz showed no ill-effects of the initial barrage, and he went to work with his ever-present volume striking. Working the head and the body, Diaz pushed Daley to the fence and seized momentum of the fight. Shockingly, it was only act two in this four-part opening-round masterpiece.

With Daley wobbled from the assault, the heavily-booed villain continued to rattle off heavy shots. Most missed, but one didn’t. Diaz was on the canvas once again. Rushing in to finish, Diaz again showed his ample heart and chin as he regained his wits underneath the onslaught of blows from the top. With Daley sensing his foe recovering, he backed away, seemingly wise for not allowing himself to tangle with the submission ace on the floor.

Yet it was only time for the Hollywood-worthy surprise ending.

With less than a minute left in a thrilling first frame, both fighters charged forward with strikes. With fists flying from all angles and bad intentions all around, both fighters found their mark. But as Diaz stumbled and turned from a right hook, Daley stumbled from an uppercut-punctuated combination and hit the deck face first. The 10-second clapper echoed in the background, and Diaz jumped in with nine unanswered follow-up blows. McCarthy jumped in, and Diaz held on to his belt in stunning fashion.

With just three seconds remaining, the stoppage could have been viewed as controversial, but cameras showed a dazed Daley struggling to get himself upright on the stool, justifying McCarthy’s call.

After outstriking Daley 54-to-36, according to CompuStrike, Diaz earned his 10th-straight win and defended the Strikeforce welterweight title for a third-straight time. With the UFC’s recent purchase of his current employer, Diaz declined to consider what might be next.

If Strikeforce light heavyweight champion Gilbert Melendez was suffering from ring rust after a near-one-year layoff, he masked it well. “El Nino” stormed Japanese superstar Tatsuya Kawajiri from the opening bell en route to a first-round shellacking of “Crusher” and his second successful defense of his belt.

Kawajiri was in trouble from the beginning, and he was dropped to a knee with an early right hand. Unfazed, Kawajiri returned to his feet determined to bang. He might have been better served remaining on that knee.

Melendez continued the assault and dumped Kawajiri on his head. The Japanese scrapper returned to his feet, but Melendez remained pinned to his back while delivering uppercuts. When the two separated to reset, it marked the beginning of the end.

After eating even more leather, Kawajiri tried for a desperation takedown. Melendez dropped down with a textbook draw and unleashed a brutal barrage of punches and elbows that left referee Cecil Peoples no choice but to call the fight at the 3:14 mark of the first round.

CompuStrike reports showed Melendez with a 45-to-15 edge in strikes, including an impressive 21 strikes on the floor.

Following the win, Melendez said he was simply executing his usual plan during the impressive result.

“That’s my style,” Melendez said. “That’s how we train. I don’t know how to fight any other way.”

Melendez (19-2 MMA, 9-1 SF), who called for a title-unification bout with the UFC’s lightweight champion, now carries a five-fight win streak. Meanwhile, Kawajiri (27-7-2 MMA, 0-1 SF) loses in his U.S. debut and falls to just 1-2 in his past three outings.

Marginal foul forces Mousasi to settle for draw

Former Strikeforce champion Gegard Mousasi appeared to leave little doubt as to the winner in his light heavyweight bout with longtime UFC contender Keith Jardine, but “The Dean of Mean” flashed both an impressive chin and an incredible heart while lasting until the final bell and “earning” a mildly controversial majority draw.

Mousasi used pinpoint striking to batter Jardine through three rounds, and while the striking specialist often found himself recovering from successful takedown attempts, he never absorbed much damage while prone. Nevertheless, it was a brief lapse in concentration while in his back that ultimately cost Mousasi a win.

With Jardine posturing over him in the opening round, Mousasi scored with an illegal upkick to the jaw. The strike wasn’t particularly powerful, and it was the first such blow of the fight, but the incredibly mustachioed referee Carlos Beltran elected to deduct a point anyway, and it would factor heavily into the final result.

Mousasi was in unquestionable control for the final 10 minutes. Accurate striking, ample takedown defense and scrambling ability left Jardine’s face a battered, bloody mess. And while the Greg Jackson-trained fighter refused to ever stop moving forward, he never really threatened Mousasi, who easily claimed the final two frames on the judges’ scorecards.

Then came the moment fight fans too often dread: the final score.

Two judges saw Jardine’s opening-round takedowns as sufficient enough to take the frame, which along with the deduction resulted in a 28-28 tie through three rounds. Just one judge saw the round as MMAjunkie.com did, 9-9, and the fight was ruled a majority draw.

Despite the apparent moral victory, likely earned by a 6-to-2 edge in takedowns according to CompuStrike, Jardine didn’t appear satisfied.

“We’re hear to win fights,” said Jardine (17-9-2 MMA, 0-0-1 SF), who took the fight on just eight-days’ notice, after the fight. “I guess they say it’s like kissing your sister.

“I got tired. I guess that’s what training camp’s for.”

A dejected Mousasi, who outstruck his foe 124-to-45 according CompuStrike, was equally frustrated.

“It happens,” Mousasi said (30-3-2 MMA, 2-1-1 SF). “In the heat of the moment, I did what I did.

“Keith is an amazing fighter, and I want to thank him for an amazing fight.”

Aoki cranks “Fancy Pants” on floor

In the evening’s first televised fight, Lyle Beerbohm showed little regard for the grappling skills of Japanese submission ace Shinya Aoki. He paid dearly for the decision.

Rather than try and exploit Aoki’s sometimes-elementary striking prowess, Beerbohm moved into a clinch early, looking for the ground. Aoki helped him find it with an outside trip that left Beerbohm on his back.

Sensing the danger, “Fancy Pants” scrambled to his knees, but Aoki simply leaped over to back control, sunk in his hooks and rolled to his own back. Holding Beerbohm on his chest, Aoki wrapped the right arm around the neck, looking for the rear-naked choke. Beerbohm tucked his chin, but Aoki simply ranked the next until his opponent could handle the pain no longer.

The entire process took just 92 seconds.

With the win, an emotional Aoki (27-6 MMA, 1-1 SF) registers his first victory under the Strikeforce banner and now carries a four-fight win streak overall. Meanwhile, the once unbeatable Beerbohm (16-2 MMA, 3-2 SF) has now suffered two consecutive defeats.